2008(率文献质量评价)Prevalence of Urinary Tract Infection in Childhood

O RIGINAL S TUDIESPrevalence of Urinary Tract Infection in ChildhoodA Meta-AnalysisNader Shaikh,MD,MPH,*Natalia E.Morone,MD,MSc,†James E.Bost,PhD,‡and Max H.Farrell,BS‡Background:Knowledge of baseline risk of urinary tract infection can help clinicians make informed diagnostic and therapeutic deci-sions.We conducted a meta-analysis to determine the pooled prev-alence of urinary tract infection(UTI)in children by age,gender, race,and circumcision status.Methods:MEDLINE and EMBASE databases were searched for articles about pediatric urinary tract infection.Search terms included urinary tract infection,cystitis,pyelonephritis,prevalence and inci-dence.We included articles in our review if they contained data on the prevalence of UTI in children0–19years of age presenting with symptoms of UTI.Of the51articles with data on UTI prevalence, 18met all inclusion criteria.Two evaluators independently re-viewed,rated,and abstracted data from each article.Results:Among infants presenting with fever,the overall preva-lence(and95%confidence interval)of UTI was7.0%(CI:5.5–8.4). The pooled prevalence rates of febrile UTIs in females aged0–3 months,3–6months,6–12months,andϾ12months was7.5%, 5.7%,8.3%,and2.1%respectively.Among febrile male infants less than3months of age,2.4%(CI:1.4–3.5)of circumcised males and 20.1%(CI:16.8–23.4)of uncircumcised males had a UTI.For the 4studies that reported UTI prevalence by race,UTI rates were higher among white infants8.0%(CI:5.1–11.0)than among black infants4.7%(CI:2.1–7.3).Among older children(Ͻ19years)with urinary symptoms,the pooled prevalence of UTI(both febrile and afebrile)was7.8%(CI:6.6–8.9).Conclusions:Prevalence rates of UTI varied by age,gender,race, and circumcision status.Uncircumcised male infants less than3 months of age and females less than12months of age had the highest baseline prevalence of UTI.Prevalence estimates can help clinicians make informed decisions regarding diagnostic testing in children presenting with signs and symptoms of urinary tract infection.Key Words:urinary tract infection,pediatrics,prevalence,meta-analysis(Pediatr Infect Dis J2008;27:302–308)P ediatric urinary tract infections(UTI)account for0.7%of physician office visits and5–14%of emergency depart-ment visits by children annually.1Accurate diagnosis of UTI has important clinical implications;most febrile infants with UTI show evidence of renal parenchymal involvement(pye-lonephritis).2Nevertheless,the presenting signs and symp-toms of UTI in childhood are often nonspecific and,among infants,definitive testing for UTI involves bladder catheter-ization.Accordingly,clinicians caring for young children are frequently faced with the decision of whether or not to obtain a urine sample for urinalysis and culture.Knowledge of the prevalence of UTI among different subgroups of children can assist clinicians in selecting chil-dren who would benefit from further diagnostic ing prevalence rates as an estimate of the prior probability of disease is thefirst step in evidence-based practice.In children with a very low pretest probability of disease,routine diag-nostic testing is not necessary.In fact,in such children,an indiscriminate approach to diagnostic testing might lead to more harm than benefit.In contrast,in children with high pretest probability of disease,routine diagnostic testing would be ap-propriate.In a survey of300academic and community pedi-atricians regarding diagnostic testing in infants with unex-plained fever,baseline risk was important in determining diagnostic decisions.3Specifically,only10%of clinicians believed that a urine culture was indicated if the probability of UTI wasϽ1%,whereas80–90%would obtain a culture if the probability of disease was3–5%,and all would do so if the probability exceeded5%.Whether a certain child has a 2%or a10%baseline probability of UTI makes a difference to the practicing clinician.Prevalence was defined as the proportion of children with the target disorder among patients undergoing diagnostic testing.4This type of point prevalence,also known as pretest probability,provides clinicians with an estimate of the base-line risk of disease.There are currently no pooled data available stratifying prevalence based on age,gender,race,or circumcision status,all of which can affect UTI risk.To address this we conducted a meta-analysis with the aim of providing clinicians with quanti-tative estimates of UTI prevalence for each subgroup.Accepted for publication October12,2007.From the*Division of General Academic Pediatrics;†Division of GeneralInternal Medicine,Center for Research on Health Care,University ofPittsburgh School of Medicine;and‡Center for Research on Health Care,University of Pittsburgh,Pittsburgh,PA.Dr.Morone was supported by the Roadmap Multidisciplinary ClinicalResearch Career Development Award Grant(1KL2RR02415401)fromthe National Institutes of Health.Address for correspondence:Nader Shaikh,MD,MPH,Children’s Hospitalof Pittsburgh,General Academic Pediatrics,3705Fifth Ave.,Pittsburgh,PA15213-2583.E-mail:nader.shaikh@.Copyright©2008by Lippincott Williams&WilkinsISSN:0891-3668/08/2704-0302DOI:10.1097/INF.0b013e31815e4122The Pediatric Infectious Disease Journal•Volume27,Number4,April2008 302METHODSAs part of a larger meta-analysis on signs and symp-toms of pediatric UTI,a large database was compiled.Twoinvestigators searched MEDLINE and EMBASE for articlesfrom January1966through October2005.Search termsincluded the following:UTI,cystitis,pyelonephritis,preva-lence,and incidence.This computerized search was supple-mented with a manual review of references cited in theTechnical Report on UTI from the American Academy ofPediatrics.5From this database,we reviewed full-text ver-sions of articles that might contain data regarding prevalenceof UTI.A second MEDLINE search was conducted6monthslater to ensure that all relevant articles were obtained.For thesecond search,the following terms were used:incidence,prev-alence,epidemiology,UTI,cystitis,and pyelonephritis.Wereviewed652titles.No additional articles were identified in thesecond search.We did not specifically search for unpublishedstudies.Articles meeting inclusion criteria were then indepen-dently reviewed,rated,and had data abstracted by2of theauthors(NS,NEM).Both authors had previous experience withdata abstraction and quality rating in meta-analysis.Explicit a priori inclusion and exclusion criteria wereapplied.We included articles in our review if they:(1)presenteddata on the prevalence of UTI in children0–19years of agepresenting with symptoms of UTI(including fever alone),(2)used urine cultures as the gold standard,and(3)defined apositive urine culture asՆ104for catheterized specimen,Ͼ103for suprapubic specimen,andՆ105for clean catch or bagspecimens.Articles were excluded if they:(1)were in languagesother than English,(2)evaluated only a high risk subgroup(eg,malnourished,premature,genitourinary or neurologic abnormal-ities,nosocomial infections,sexually abused),(3)were per-formed in developing countries,(4)evaluated only a low risksubgroup(eg,asymptomatic well appearing children),(5)eval-uated only children with other symptomatic illnesses(febrileseizures,infectious diarrhea,bronchiolitis),(6)containedfewer than10subjects,and(7)used bags to collect urinespecimen in more than25%of subjects with UTI withoutconfirming results using more accurate methods such assuprapubic catheterization or bladder catheterization.Four of the authors whose prevalence papers are in-cluded in this analysis(Zorc,Newman,Hoberman,andShaw)provided us with additional data from their studies,which we included in our analyses.Quality Rating.We used a published quality rating system forprevalence articles.6Two investigators(NS,NEM)assessedeach study independently on a5-point scale.We reviewedeach article to determine whether:(1)study design wasappropriate for obtaining prevalence estimates,(2)samplewas representative of the general population of children present-ing with a UTI,(3)UTI diagnostic criteria were acceptable(catheterized,suprapubic,or clean catch specimen withϾ105,Ͼ103,andϾ105organisms,respectively),(4)urine culture was performed on a consecutive or random sample of sub-jects,and(5)thefinal diagnosis was known forϾ80%ofeligible subjects.To avoid introducing bias,we included allarticles meeting our inclusion criteria in the analysis,andused the quality rating to explore the effect of study quality on prevalence values.7Disagreements were resolved by con-sensus of the authors.Statistical Analysis.Data were imported into STATA version 9.2and a pooled estimate of UTI prevalence was calculated.To determine whether or not to use thefixed-or random-effects model,statistical heterogeneity between and within groups was measured using the Q statistic and assessed visually using the Galbraith plot of heterogeneity.If the Q test was not significant, thefixed effects methods were used.Otherwise pooled estimates and confidence intervals were calculated assuming a random-effects model with inverse-variance weighting using the DeSimonian and Laird method.8Although we did not expect to see publication bias when assessing prevalence,this was assessed using the Begg rank correlation method and the Egger weighted regression method. We also looked at the cumulative effect of adding articles one at a time ordered by publication date on the pooled prevalence estimate.We also performed a similar analysis for quality ratings.To evaluate the weight of particular articles on the pooled estimate we performed influence analysis.This method recalculates the pooled prevalence estimate omitting1study at a time.Meta-regression was used to analyze the relationship between UTI prevalence and study quality,age,length of the study,setting(outpatient clinic versus ER),year of study,and whether the study was conducted in the United States or another country.All reported confidence intervals represent the95% confidence intervals.RESULTSDescription of Articles.From a total ofϾ4000articles found through our search strategy,we retrieved330for full text review.Fifty-one articles contained prevalence data and of these18articles evaluating22,919children met all criteria for inclusion.The setting for all articles was either the outpatient clinic,emergency department or both.There was no evidence of publication bias.We categorized the studies into2groups based on the population of children enrolled.There were14articles which enrolled infants(0–24 months,Table1);in these articles,enrollment was based on the presence of fever(of at least38.0°C).We further subdi-vided this group into4smaller subgroups:infantsՅ3 months,infants3–6months,infants6–12months,and in-fants12–24months of age.There were4articles which enrolled children older than 2years of age(Table2).In these studies,enrollment was based on the presence of signs and symptoms referable to the urinary tract.Although some infants(with fever)were in-cluded in these studies,the majority of subjects were children Ͼ2years of age(with urinary symptoms).Prevalence of UTI Among Febrile InfantsϽ2Years of Age. Among the14studies of febrile infantsϽ24months of age, the pooled prevalence of UTI was7.0%(CI:5.5–8.4)(Fig.1). The␹2test of homogeneity was highly significant(PϽ0.001). Accordingly random effects estimates were used.The Begg and Egger tests showed no evidence of publication bias.The Gal-braith plot,identified the populations studied by Newman et al,9 Bachur and Harper,10and Shaw et al11as the most heteroge-neous.However,influence analysis showed that no study,in-The Pediatric Infectious Disease Journal•Volume27,Number4,April2008Prevalence of Urinary Tract Infectioncluding these3,significantly impacted the pooled prevalence estimate.Although high study quality was associated with lower prevalence of UTI(Pϭ0.001),only small changes in the pooled prevalence rate was observed after eliminating the2 bag studies(6.6,CI:5.1–8.1)or the2level4studies6.6% (5.1–8.1%).Meta-regression showed that study year,study length,location within the United States,and study setting did not impact prevalence rates significantly.The effect of age and gender on prevalence of febrile UTI in infants is shown in Table1.Fourteen articles contained data regarding the prevalence of UTI among febrile infants,9of which presented data according to gender.Among males,prev-alence rates were highest during thefirst3months of life and declined thereafter.Among females,prevalence rates were high-est during thefirst12months.Prevalence of Febrile UTI According to Circumcision Status. Four articles contained information regarding UTI prevalence in circumcised and uncircumcised males in infantsϽ3months of age(Fig.2).9,11–14The UTI prevalence rates for circumcised and uncircumcised males were2.4%(CI:1.4–3.5)and20.1%(CI: 16.8–23.4),respectively.The prevalence of UTI among circum-cised males was relatively similar across the articles.Elimination of the bag studies from this analysis did not significantly alter the results:prevalence of UTI among uncircumcised(2studies)and circumcised infants(1study)was20.7%(CI:16.7–20.8)and 2.3%(CI:1.1–5.4),respectively.TABLE1.Prevalence of Urinary Tract Infection Among Febrile Infants0–24Months of Age Stratified by AgeStudy Characteristics Prevalence of Urinary Tract Infection(%)Quality*Setting Country Age N†Overall Females Males Circumcised Uncircumcised Infants<3Mo With FeverKrober et al,2319851Clinic USAϽ3mo18211.07.214.1Crain and Gershel,121990‡3ED USAϽ2mo4427.5 4.110.1 2.117.5 Bonadio et al,2419931ED USAϽ2mo233 2.9Bonadio et al,2519931ED USAϽ2mo1130 3.5Hoberman et al,1519932ED USAϽ3mo391 5.48.9 2.4Bonadio et al,2619942ED USA8–12wk321 5.3Shaw et al,1119982ED USAϽ3mo335 5.49.4 1.7Lin et al,1320002Clinic/ED TaiwanϽ2mo16213.6 5.919.119.1 Kadish et al,2720003ED USAϽ1mo3728.6Bachur and Harper,1020014ED USAՅ3mo37687.1Herr et al,2820011ED USAϽ2mo434 5.79.0 2.7Dayan et al,2920021ED USAϽ2mo23211.6 5.118.4Newman et al,92002‡4Clinic USAϽ3mo160810.413.07.4 2.620.8Zorc et al,1420052ED USAϽ2mo10059.0 5.012.0 2.321.3 Pooled prevalence(CI)7.2(5.8–8.6)7.5(5.1–10.0)8.7(5.4–11.9)2.4(1.4–3.5)20.1(16.8–23.4) Infants3–6mo With FeverHoberman et al,1519932ED USA3–6mo171 2.9 3.7 2.2Shaw et al,1119981ED USA3–6mo390 5.67.5 4.2Bachur and Harper,1020014ED USA3–6mo171110.9Pooled prevalence(CI) 6.6(1.7–11.5) 5.7(2.3–9.4) 3.3(1.3–5.3)Infants6–12mo With FeverHoberman et al,1519932ED USA6–12mo390 6.210.9 2.7Shaw et al,1119982ED USA6–12mo1030 3.7 6.5 1.30.37.3 Bachur and Harper,1020014ED USA6–12mo3114 6.4Pooled prevalence(CI) 5.4(3.4–7.4)8.3(3.9–12.7) 1.7(0.5–2.9)Infants12–24mo With FeverShaw et al,1119982ED USA12-24mo656 2.1Bachur and Harper,1020014ED USA12-24mo2928 4.5Pooled Prevalence of FebrileUTI in Infants0–24moof AgePooled prevalence(CI)7.0(5.5–8.4)7.3(5.0–9.6)8.0(5.5–10.4)*Quality rated from1to5using published criteria5with1being the best quality and5being the worst quality(see Methods).†Three studies provided data stratified by age(Bachur,Shaw,Hoberman);for these studies,N represents number of children in the respective age group.‡20–25%of positive urine cultures from bag specimen.For this analysis,children with growth ofՅ105CFU/mL from bag specimen and a negative UA were considered not to have a UTI.ED indicates Emergency Department;CI,95%confidence interval.TABLE2.Prevalence of UTI in ChildrenϽ19Years With Urinary Symptoms and/or FeverQuality*Setting Country Age N Prevalence Heale et al,3019732Clinic/ED AustraliaϽ15yr7899.1Dickinson,3119792Clinic UKϽ15yr1568.9Shaw and McGowan,3219973ED USAϽ19yr12987.1Struthers et al,3320033Clinic/ED UKϽ6yr110 6.4Pooled prevalence(CI)7.8(6.6–8.9)ED indicates Emergency Department;CI,95%confidence interval.Shaikh et al The Pediatric Infectious Disease Journal•Volume27,Number4,April2008One study provided data regarding prevalence of UTI among older infants by circumcision status.In that study the prevalence rates of UTI among circumcised and uncircum-cised males 6–12months of age were 0.3%and 7.3%,respectively.None of the studies included data regarding the prevalence of UTI in males Ͼ12months of age.Prevalence of Febrile UTI According to Race.Four articles provided data regarding race.9,11,14,15The prevalence of UTI among whites (8.0%;CI:5.1–11.0)was significantly higher than the prevalence of UTI among African Americans (4.7%;CI:2.1–7.3).However,there was heterogeneity among the articles.Three articles found significantly higher rates of UTI among whites than African Americans.9,11,15In the remaining study,14which used Hispanics as a race cate-gory,whites were less likely to have a UTI than nonwhites.Because Hispanic males are less likely to be circum-cised,16,17the higher rate of UTI among nonwhites may be partially the result of the Hispanic male subgroup.Among female children,all 4studies found higher rates of UTI among whites than African Americans.Prevalence of UTI Among Older Children.Four studies presented data on the prevalence of UTI among children Ͻ19years of age with signs or symptoms referable to the urinary tract (Table 2).The ␹2test indicated that the studies were homogeneous (P ϭ0.36).The pooled prevalence of UTI (febrile and afebrile)was 7.8%(CI:6.6–8.9).DISCUSSIONThis analysis found that the reported prevalence of UTI varies widely by age,gender and circumcision status.This confirms the importance of demographic and clinical charac-teristics when considering further diagnostic testing.The quantitative prevalence estimates presented in this article provide the clinician with a better sense of the relative importance of each of these factors.By incorporating infor-mation about the patient’s age,race,gender and circumcision status,clinicians can make more informed decisions on a case-by-case basis.We found slightly higher prevalence rates than a 1999study of UTI prevalence conducted by the American Acad-Source Sample Size Krober, 1985182Crain, 1990442Bonadio, 19931,130Bonadio, 1993233Hoberman, 1993945Bonadio, 1994321Shaw, 19982,411Kadish, 2000372Lin, 2000162Bachur, 200111,089Herr, 2001434Dayan, 2002232Newman, 20021,608Zorc, 20041,005Aged 0 - 24 MonthsSource Sample Size Heale, 1973789Dickinson, 1979156Shaw, 19971,298Struthers, 2003110Prevalence, %FIGURE 1.Urinary tract infection prevalence (rectangles),95%confidence interval (lines),and pooled prevalence rate (diamonds)stratified by age.The Pediatric Infectious Disease Journal •Volume 27,Number 4,April 2008Prevalence of Urinary Tract Infectionemy of Pediatrics(AAP)in which the pooled prevalence of UTI in10studies was5%.5We used explicit a priori inclusion and exclusion criteria specifically related to prevalence studies, which led us to exclude several articles included in the AAP report.Furthermore,we were able to provide pooled estimates of prevalence by age,race and gender.Female infants with fever had a relatively high prevalence rate of UTI,especially during thefirst year of life.Our results are consistent with data from large epidemiologic UTI studies,18,19 which have shown a decreasing incidence of febrile UTI among females during thefirst2years of life.Accordingly,it would be reasonable to consider obtaining a urine specimen from febrile females younger than1year of age.Knowledge of the baseline probability of UTI,along with information on the unique clinical presentation,can help the clinician decide whether obtaining a urine specimen is indicated.Among febrile males,circumcision status was impor-tant in determining risk for UTI.Uncircumcised male infants Յ3months of age had the highest prevalence of UTI of anygroup,male or female,whereas circumcised males had one of the lowest rates.Among febrile male infantsՅ3months of age,20.1%of uncircumcised males had a UTI.Thisfinding suggests that clinicians need to carefully ascertain circumci-sion status in all male infants with unexplained fever.Among studies with circumcised male infantsՅ3months of age,the prevalence of UTI was2.4%.Accordingly,approximately42 such infants will need to undergo catheterization to detect a single UTI.Although the prevalence of UTI is relatively low in this subgroup,the risks of a misdiagnosed neonatal UTI (hematogeneous dissemination,sepsis,missed high grade vesicoureteral reflux)are high.Furthermore,in this age group more than any other,appropriate therapy depends on deter-mination of the exact site and bacterial etiology of the infecting agent.Accordingly,catheterization of all febrile male infantsϽ3months of age should be considered.Although we could not directly calculate the pooled prevalence of UTI in circumcised and uncircumcised males older than1year of age from the included articles,several important pieces of information are available.Among the studies compiled for this report,the overall prevalence of UTIFIGURE2.Urinary tract infection prevalence(rectangles),95%confidence interval(lines),and pooled prevalence rate(diamonds) for circumcised and uncircumcised male infants younger than3months of age.Shaikh et al The Pediatric Infectious Disease Journal•Volume27,Number4,April2008among males decreased rapidly with age(Table1).This is consistent with previous epidemiologic studies of UTI in which the highest rates of UTI were in thefirst month of life.18,20The decreasing prevalence of UTI with age has been documented in uncircumcised18–21and circumcised males.10,11 In these epidemiologic studies,the rates of UTI decrease con-siderably after6or12months of age.Only one of the studies that included older male infants reported UTI prevalence by circumcision status;among circumcised male infants6–12 months of age,the prevalence of UTI was0.3%among uncir-cumcised males and7.3%among circumcised males.19Accord-ingly,it would be reasonable to assume that the prevalence of UTI among circumcised malesϾ12months of age isϽ1%.The available data suggest that race is associated with UTI prevalence.Although more data are needed to clarify the mech-anism by which race affects baseline risk of UTI,based on the available data,white children can be considered at higher risk of developing UTI than African American children.Among older children with signs and symptoms referable to the urinary tract,the prevalence of UTI was7.8%(CI: 6.6–8.9).In contrast,among adult females presenting with genitourinary symptoms,approximately50%are ultimately di-agnosed with UTI.22The discrepancy between children and adults could be secondary to biologic differences such as sexual activity or bacterialflora.Alternatively,it could be related to the better ability of adults to recognize and communicate symptoms of UTI.Whatever the reasons,the difference in pretest proba-bility dictates a different approach to diagnosis.Specifically,the relatively low prevalence of UTI in children calls for the use of more accurate tests to minimize false positive and false negative results.Furthermore,because of the relatively low prevalence of UTI in children,diagnosis of UTI based on signs or symptoms alone is unlikely to be accurate.Our analysis had several limitations.First,the hetero-geneity(among studies of infantsՅ2years)could be con-sidered a limitation.Although pooled estimates and the con-fidence intervals include adjustments for the between study variances,clinical judgment is warranted to decide whether, in fact,there are studies that were“too different”to be included.We found little difference in study design or quality between studies having the greatest and least impact on heterogeneity.Second,because most of the articles about older children did not differentiate cystitis from pyelonephri-tis,the estimates provided include both.Finally,we could not directly calculate a prevalence rate for verbal children ac-cording to gender as no study that included older children reported this data.This analysis,however,has several strengths.By using rigorous methodology(comprehensive search strategy and use of a priori inclusion/exclusion criteria),our results pro-vide a more updated picture of UTI prevalence.The pooled estimates have relatively narrow confidence intervals and are consistent with previous epidemiologic studies.Pooled prev-alence values provided in this study can be used as an estimate of baseline probability in an evidence-based ap-proach.Neither cumulative incidence nor population preva-lence,often reported in epidemiologic articles,can be used in this fashion.In pediatrics,signs and symptoms of disease are often nonspecific.Consequently,more prevalence meta-anal-yses are needed to provide clinicians with baseline estimates of risk for common diseases.ACKNOWLEDGMENTSDr.Shaikh had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.The authors thank Drs. Gorelick,Newman,Zorc,Lin and Hoberman for providing us with additional data from their studies.REFERENCES1.Freedman AL.Urologic diseases in North America Project:trends inresource utilization for urinary tract infections in children.J Urol.2005;173:949–954.2.Hoberman A,Charron M,Hickey RW,Baskin M,Kearney DH,WaldER.Imaging studies after afirst febrile urinary tract infection in young children.N Engl J Med.2003;348:195–202.3.Roberts KB,Charney E,Sweren RJ,et al.Urinary tract infection ininfants with unexplained fever:a collaborative study.J Pediatr.1983;103:864–867.4.Haynes RB,Sackett DL,Guyatt GH,Tugwell P.Clinical Epidemiology:How to Do Clinical Practice Research.3rd ed.Philadelphia,PA: Lippincott Williams&Wilkins;2006.5.Downs SM.Technical report:urinary tract infections in febrile infantsand young children.Pediatrics.1999;103:e54.6.Richardson WS,Polashenski WA,Robbins BW.Could our pretestprobabilities become evidence based?A prospective survey of hospital practice.J Gen Intern Med.2003;18:203–208.7.Juni P,Witschi A,Bloch R,Egger M.The hazards of scoring the qualityof clinical trials for meta-analysis.JAMA.1999;282:1054–1060.8.DerSirmonian R,Laird N.Meta-analysis in clinical trials.Control ClinTrials.1986;7:177–188.9.Newman TB,Bernzweig JA,Takayama JI,Finch SA,Wasserman RC,Pantell RH.Urine testing and urinary tract infections in febrile infants seen in office settings:the Pediatric Research in Office Settings’Febrile Infant Study.Arch Pediatr Adolesc Med.2002;156:44–54.10.Bachur R,Harper MB.Reliability of the urinalysis for predicting urinarytract infections in young febrile children.Arch Pediatr Adolesc Med.2001;155:60–65.11.Shaw KN,Gorelick M,McGowan KL,Yakscoe NM,Schwartz JS.Prevalence of urinary tract infection in febrile young children in the emergency department.Pediatrics.1998;102:e16.12.Crain EF,Gershel JC.Urinary tract infections in febrile infants youngerthan8weeks of age.Pediatrics.1990;86:363–367.13.Lin DS,Huang SH,Lin CC,et al.Urinary tract infection in febrileinfants younger than eight weeks of Age.Pediatrics.2000;105:E20. 14.Zorc JJ,Levine DA,Platt SL,et al.Clinical and demographic factorsassociated with urinary tract infection in young febrile infants.Pediat-rics.2005;116:644–648.15.Hoberman A,Chao HP,Keller DM,Hickey R,Davis HW,Ellis D.Prevalence of urinary tract infection in febrile infants.J Pediatr.1993;123:17–23.16.Risser JM,Risser WL,Eissa MA,Cromwell PF,Barratt MS,Bortot A.Self-assessment of circumcision status by adolescents.Am J Epidemiol.2004;159:1095–1097.umann EO,Masi CM,Zuckerman EW.Circumcision in the UnitedStates.Prevalence,prophylactic effects,and sexual practice.JAMA.1997;277:1052–1057.18.Jakobsson B,Esbjorner E,Hansson S.Minimum incidence and diag-nostic rate offirst urinary tract infection.Pediatrics.1999;104:222–226.19.Marild S,Jodal U.Incidence rate offirst-time symptomatic urinary tractinfection in children under6years of age.Acta Paediatr.1998;87:549–552.20.Winberg J,Andersen HJ,Bergstrom T,Jacobsson B,Larson H,LincolnK.Epidemiology of symptomatic urinary tract infection in childhood.Acta Paediatr Scand Suppl.1974;252:1–20.21.Uhari M,Nuutinen M.Epidemiology of symptomatic infections of theurinary tract in children.BMJ.1988;297:450–452.22.Bent S,Nallamothu BK,Simel DL,Fihn SD,Saint S.Does this womanhave an acute uncomplicated urinary tract infection?JAMA.2002;287: 2701–2710.The Pediatric Infectious Disease Journal•Volume27,Number4,April2008Prevalence of Urinary Tract Infection。